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Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

Q2 Z2,(Q2) Z2(Q2) - Institute for Water Resources - U.S. Army

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S = speed in miles per hour<br />

W = width of waterway in feet<br />

B = breadth of flotilla in feet<br />

L = length of flotilla in feet<br />

HP = horsepower of the towboat<br />

The resistance of a flotilla as it is pushed through the waterway<br />

depends on its velocity, the characteristics of the flotilla (length,<br />

breadth, and draft), and the characteristics of the waterway (depth, and<br />

width). The push generated by a towboat depends upon the horsepower<br />

and speed of the boat and the depth of the waterway. The equilibrium<br />

condition, given in (3), must hold <strong>for</strong> a tow operating at a constant<br />

speed.<br />

Since naval design theory does not provide the exact <strong>for</strong>m - of<br />

either the resistance function or the effective push function, it was<br />

necessary <strong>for</strong> Howe to estimate the parameters of the two relationships<br />

statistically. The data used to estimate the functions were derived<br />

from tank and prototype tests conducted by the U. S. <strong>Army</strong> Corp of<br />

Engineers and barge equipment manufacturers, and speed tests conducted<br />

with actual equipment by barge operators.<br />

According to Howe, "Extensive use of regression analysis showed<br />

that the following functional <strong>for</strong>m fitted the resistance test data<br />

quite well:" (p. 27).<br />

(4) R.= ao eal (1/D-0<br />

s a2 Ha3 + a4<br />

(1/W-B) a .<br />

L 5 Ba6<br />

This, Howe used as a modified log-linear resistance function which is<br />

n . . . consistent with what is known about resistance phenomena." (p. 27).<br />

15

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